Components and catalysts for the polymerization of olefins

ABSTRACT

The present invention relates to components of catalysts for the polymerization of olefins comprising a metallocene compound and a magnesium halide which have particular values of porosity and surface area. In particular the components of the invention have surface area (BET) greater than about 50 m 2 /g, porosity (BET) greater than about 0.15 cm 3 /g and porosity (Hg) greater than 0.3 cm 3 /g, with the proviso that when the surface area is less than about 150 m 2 /g, the porosity (Hg) is less than about 1.5 cm 3 /g. The components of the invention are particularly suitable for the preparation of catalysts for the gas-phase polymerization of α-olefins.

[0001] The present invention relates to components of catalysts for thepolymerization of olefins, the catalysts obtained therefrom and the useof said catalysts in the polymerization of olefins CH₂═CHR, in which Ris hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbonatoms. Another aspect of the present invention relates to the polymersobtained using said catalysts.

[0002] Catalysts are known from the literature that are obtained fromcompounds ML_(x) in which M is a transition metal, especially Ti, Zr andHf, L is a ligand coordinating on the metal, x is the valence of themetal and at least one of the ligands L has cyclo-alkadienyl structure.Catalysts of this type using compounds Cp₂TiCl₂ or Cp₂ZrCl₂(Cp=cyclopentadienyl) are described in U.S. Pat. Nos. 2,827,446 and2,924,593. The compounds are used together with alkyl-Al compounds inthe polymerization of ethylene. The catalytic activity is very low.Catalysts with very high activity are obtained from compounds Cp₂ZrCl₂or Cp₂TiCl₂ and from their derivatives substituted in thecyclopentadienyl ring, in which the Cp ring can also be condensed withother rings, and from polyalumoxane compounds containing the repeatingunit —(R)AlO—, in which R is a lower alkyl, preferably methyl (U.S. Pat.No. 4,542,199 and EP-A-129368).

[0003] Catalysts of the type mentioned above, in which the metallocenecompound contains two indenyl or tetrahydroindenyl rings bridge-bondedthrough lower alkylenes or through other divalent radicals, are suitablefor the preparation of stereoregular polymers of propylene and otherα-olefins (EP-A-185918).

[0004] Stereospecific catalysts are also obtained fromdicyclopentadienyl compounds in which the two rings are substituteddifferently with groups having steric hindrance such as to preventrotation of the rings about the axis of coordination with the metal.

[0005] Substitution of indenyl or tetrahydroindenyl in suitablepositions gives catalysts that have very high stereospecificity(EP-A-485823, EP-A-485820, EP-A-519237, U.S. Pat. No. 5,132,262 and U.S.Pat. No. 5,162,278).

[0006] The metallocene catalysts described above produce polymers with avery narrow molecular weight distribution (Mw/Mn of about 2).

[0007] Some of these catalysts also have the property of formingcopolymers of ethylene with α-olefins of the LLDPE type orethylene/propylene elastomeric copolymers with very uniform distributionof the comonomer units. The LLDPE polyethylene obtained is furthercharacterized by low solubility in solvents such as xylene or n-decane.

[0008] The polypropylene obtained with the highly stereospecificcatalysts mentioned above has greater crystallinity and a higherdeformation temperature compared with the polymer that can be obtainedwith the conventional Ziegler-Natta catalysts.

[0009] However, these metallocene catalysts have a considerable drawbackwith respect to the possibility of being employed in industrialprocesses for production of polyolefins that are not carried out insolution, owing to the fact that they are soluble in the reaction mediumin which they are prepared and in the liquid medium of polymerization.

[0010] In order to be usable in gas-phase polymerization processes, thecatalysts must be supported on suitable supports which endow the polymerwith appropriate morphological properties.

[0011] Supports of various kinds have been used, including, amongothers, porous metal oxides such as silica or porous polymeric supportssuch as polyethylene, polypropylene and polystyrene. The halides ofmagnesium are also used as supports. In some cases magnesium halides arealso used as counterion of an ion pair in which the metallocene compoundsupplies the cation and a compound, such as a Mg halide, supplies theanion.

[0012] When Mg halide is used for supplying the anion, the catalyticsystem is formed by the halide present in solid form and the metallocenecompound dissolved in a solvent. A system of this type cannot be used ingas-phase polymerization processes. Mg halide is preferably used infinely divided form that can be obtained by grinding.

[0013] As support, Mg halide is used in pulverized form, obtainable bygrinding. Catalysts obtained in this way are not of high performance.Sufficiently high yields can only be obtained when the Mg halide is usedin a form in which it is partially complexed with an electron-donorcompound, obtained by a special method of preparation.

[0014] Japanese Application No. 168408/88 (published on Dec. 7, 1988)describes the use of magnesium chloride as support for metallocenecompounds, such as Cp₂TiCl₂, Cp₂ZrCl₂, Cp₂Ti(CH₃)₂ for forming, withtrialkyl aluminium and/or polymethylalumoxane (MAO), catalysts for thepolymerization of ethylene. The component containing the magnesiumchloride is prepared by grinding MgCl₂ with the metallocene compound,also working in the presence of electron-donor compounds. Alternatively,the component is prepared by treating the metallocene with a liquidMgCl₂-alcohol adduct and subsequent reaction with AlEt₂Cl. The catalystactivity, referred to MgCl₂ is very low.

[0015] Catalysts comprising a metallocene compound of the type Cp₂ZrCl₂supported on MgCl₂ in spherical form and partially complexed with anelectron-donor compound are described in U.S. Pat. No. 5,106,804. Theperformance of these catalysts is better than that described in JapaneseApplication No. 168408/88 but is still not satisfactory, since it is notpossible to obtain polymers containing sufficiently low residues of thecatalyst. The electron donor used must be free from atoms of activehydrogen and in addition must be uniformly distributed in the bulk ofthe Mg halide. Suitable supports cannot be obtained by mere mixing ofthe components. Homogeneous dispersion of the electron donor is obtainedby forming the Mg halide (by halogenation of Mg-dialkyls) in thepresence of a solvent containing the electron donor in dissolved form.The surface area of the Mg halide is not greater than 100 m²/g, and ispreferably between 30 and 60 m²/g. No information is given with respectto the porosity of the support. The electron-donor compound is used in aquantity of from 0.5 to 15 mol % based on the Mg halide; its presence isnecessary. The catalysts obtained have performance that is much lowerthan that of the corresponding unsupported catalysts in which themetallocene compound is used in solution.

[0016] Application EP-A-318048 describes catalysts in which a solidcomponent comprising a compound of Ti supported on a magnesium chloridethat has particular characteristics of surface area and of porosity andpossibly an electron-donor compound, is used with benzyl compounds of Tior Zr or with metallocene compounds of the type Cp₂Ti(CH₃)₂ andbis-(indenyl)-Zr(CH₃)₂ for forming catalysts for polymerization ofethylene and of propylene. The weight ratio of metallocene to magnesiumchloride is very high (greater than 1), so it is necessary to remove themetallocene from the obtained polymer. The catalysts are used inprocesses that are carried out in the presence of a liquidpolymerization medium.

[0017] Application EP-A-439964 describes bimetallic catalysts suitablefor the preparation of ethylene polymers with broad molecular weightdistribution (Mw/Mn between 4 and 14) obtained by supporting ametallocene on a solid component containing a Ti compound supported onMgCl₂. MAO or its mixtures with alkyl-Al are used as cocatalyst.Trialkyl-Al compounds are also used as cocatalysts but the catalyticactivity is low. The yields of these mixed catalysts with active centresderived either from the Ti compound supported on MgCl₂ or from themetallocene compound are very high when the catalysts are used in ahydrocarbon medium; on the other hand they are low when polymerizationis effected in the gas phase. This is probably due to the fact that,when using a hydrocarbon medium, as the metallocene compound is notfixed to the support in a stable form, it dissolves in the hydrocarbonpolymerization solvent. In practice, the obtained catalyst correspondsto a homogeneous catalyst in which the metallocene compound is used insolution. Working in the gas phase, the metallocene compound is presentas a solid and the catalyst obtained therefrom has an activity lowerthan that of the corresponding catalyst used in solution.

[0018] Application EP-A-522281 describes catalysts obtained fromCp₂ZrCl₂ supported on MgCl₂ and from mixtures of trialkyl-Al andcompounds supplying stable anions of the typedimethylaniline-tetrakis-(pentafluorophenyl)-borate. The catalysts areprepared by grinding the components and are used to polymerize ethylenein the presence of a solvent (toluene) with good yields (based onMgCl₂). In this case too, the metallocene compound is present largely insolution and not fixed to MgCl₂ and the relatively high activity basedon MgCl₂ is due essentially to the catalyst dissolved in thepolymerization medium.

[0019] Application EP-A-509944 describes catalysts usinganiline-tetrakis-(pentafluorophenyl)-borate or Lewis acids such as MgCl₂together with metallocene halides pre-reacted with alkyl-Al compounds.The magnesium chloride is ground before being contacted with thepre-reacted metallocene compound. The yields of polymer based on the Mghalide are not high (less than about 100 g polymer/g MgCl₂). The Mghalide has surface are between 1 and 300 m²/g, preferably between 30 and300 m²/g. Mg chloride with area between 30 and 300 m²/g is obtainedessentially by grinding the commercial chloride. In this case it isdifficult for the area to exceed 100-150 m²/g and the porosities arerelatively low (less than 0.1 cm³/g). Also in the case of the catalystsdescribed in Application EP-A-509944 the yields should largely beattributed to the metallocene compound dissolved in the polymerizationsolvent.

[0020] Application EP-A-588404 describes catalysts obtained frommetallocene compounds supported on Mg halides prepared by halogenationof dialkyl-Mg or alkyl-Mg halides with SiCl₄ or SnCl₄. The yields ofpolymer (polyethylene) per g of solid component and per g of Zr arerelatively high, especially when the catalyst is obtained from MgCl₂prepared using SnCl₄. Again in this case it is to be assumed that thehigh catalytic activity is due more to the catalyst derived from themetallocene compound that dissolves in the polymerization medium thanfrom that derived from the metallocene compound actually supported onthe Mg halide.

[0021] European Application EP-A-576213 describes catalysts obtainedfrom a solution of MgCl₂ in an alkanol, from a trialkyl-Al compound andfrom a metallocene compound. The yields of polymer are very low. Thecatalyst is practically inactive when the MgCl₂ solution is replaced bysolid MgCl₂ activated by prolonged grinding.

[0022] Solid components have now unexpectedly been found that comprise ametallocene compound and a magnesium halide, capable of giving catalyststhat have very high activity in the polymerization of olefins,characterized by surface area (BET method) greater than about 50 m²/g,porosity (BET method) greater than about 0.15 cm³/g and porosity (Hgmethod) greater than 0.3 cm³/g, with the proviso that when the surfacearea is less than about 150 m²/g, the porosity (Hg) is less than about1.5 cm³/g.

[0023] The porosity and surface area according to the BET method aredetermined using the “SORPTOMATIC 1800” apparatus from Carlo Erba.

[0024] The porosity according to the Hg method is determined using a“Porosimeter 2000 series” porosimeter from Carlo Erba, following theprocedure described below.

[0025] The porosity (BET) is preferably above 0.2 cm³/g and inparticular between 0.3 and 1 cm³/g. The surface area (BET) is preferablygreater than 100 m²/g and more preferably greater than 150 m²/g. A veryconvenient range is between 150 and 800 m²/g. Components with surfacearea less than 150 m²/g give catalysts with performance that is ofinterest, provided that the porosity (Hg method) is less than about 1.5cm³/g, preferably between 0.4 and 1.2 cm³/g, and in particular between0.5 and 1.1 cm³/g.

[0026] The components are preferably used in the form of sphericalparticles smaller than 150 μm.

[0027] In the components with surface area (BET) less than 150 m²/g morethan 50% of the porosity (BET) is due to pores with radius greater than300 Å and preferably between 600 and 1000 Å.

[0028] The components with surface area (BET) greater than 150 m²/g andin particular greater than 200 m²/g exhibit, along with porosity (BET)due to pores with radius between 300 and 1000 Å, also porosity (BET) dueto pores with radius between about 10 and 100 Å. In general, more than40% of the porosity (BET) is due to pores with radius greater than 300Å.

[0029] The mean dimensions of the crystallites of Mg halide present inthe solid component are generally below 300 Å and more preferably below100 Å. The definition of the components of the invention also includesthose components which, in normal conditions, do not display the valuesof area and porosity stated above but attain them after treatment with asolution of trialkyl-Al at 10% in n-hexane at 50° C. for 1 hour.

[0030] The components of the invention are prepared by supporting ametallocene compound on an Mg halide or on a support containing Mghalide that has characteristics of surface area and of porosity that arewithin the ranges stated for the catalytic component.

[0031] In general the surface area (BET) and the porosity (BET) andporosity (Hg) of the starting magnesium halide are greater than those ofthe component obtained from it.

[0032] Preferred Mg halides have surface area (BET) greater than 200m²/g and more preferably between 300 and 800 m²/g and porosity (BET)greater than 0.3 cm³/g.

[0033] The Mg halide can comprise, in smaller proportions, othercomponents acting as co-support or used for improving the properties ofthe catalytic component. Examples of these components are AlCl₃, SnCl₄,Al(OEt)₃, MnCl₂, ZnCl₂, VCl₃, Si(OEt)₄.

[0034] The Mg halide can be complexed with electron-donor compounds notcontaining active hydrogen in a quantity up to about 30 mol %,preferably 5-15 mol % based on the Mg halide. Examples of electrondonors are ethers, esters, ketones.

[0035] The Mg halide can in its turn be supported on an inert supportthat has area and porosity such that the supported product has thevalues stated above. Suitable inert supports can be metal oxides such assilica, alumina, silica-alumina, possessing porosity (BET) greater than0.5 cm³/g and surface area (BET) greater than 200 m²/g and for examplebetween 300 and 600 m²/g,

[0036] Other inert supports can be porous polymers such as polyethylene,polypropylene and polystyrene.

[0037] Partially crosslinked polystyrene that has high values of surfacearea and porosity is particularly suitable.

[0038] Polystyrenes of this type are described in U.S. Pat. No.5,139,985, whose description of the method of preparation and supportingof the magnesium halide is included here for reference. Thesepolystyrenes generally have surface area (BET) between 100 and 600 m²/gand porosity (BET) greater than 0.5 cm³/g.

[0039] The amount of Mg halide that can be supported is generallybetween 1 and 20% by weight based on the mixture. The preferred Mghalide is Mg chloride. The Mg halide can be supported according to knownmethods, starting from its solutions in solvents such as tetrahydrofuranor by impregnation of the inert support with solutions of the halide inan alcohol; the alcohol is then removed by reaction with a compound suchas a trialkyl-Al or dialkyl-Al halide or silicon halides. The alcoholsused are generally alkanols with 1-8 carbon atoms.

[0040] A method that is very suitable for preparation of Mg halides thathave the characteristics of porosity and area stated above, consists ofreacting spherulized adducts of MgCl₂ with alcohols, the said adductscontaining from 0.1 to 3 mol of alcohol with alkyl-Al compounds, inparticular triethyl-Al, triisobutyl-Al, AlEt₂Cl.

[0041] A preparation of this type is described in U.S. Pat. No.4,399,054 whose description is herein included for reference.

[0042] For the purpose of obtaining supports with morphologicalcharacteristics that are particularly suitable for gas-phasepolymerization processes in a fluidized bed, the adduct of MgCl₂ withabout 3 mol of alcohol should be submitted, prior to reaction with thealkyl-Al, to a controlled partial dealcoholizing treatment such as thatdescribed in European Patent Application EP-A-553806, to which referenceis made for the description. The Mg halides thus obtained have aspheroidal shape, mean dimensions less than 150 microns, surface area(BET) greater than 60-70 m²/g and generally between 60 and 500 m²/g.

[0043] Other methods of preparation of the Mg halides suitable forpreparation of the components of the invention are those described inEuropean Patent Application EP-A-553805, whose description is hereinincluded for reference.

[0044] Supporting of the metallocene compound is carried out accordingto known methods by bringing the Mg halide into contact, for example,with a solution of the metallocene compound, operating at temperaturesbetween room temperature and 120° C. The metallocene compound that isnot fixed on the support is removed by filtration or similar methods orby evaporating the solvent.

[0045] The amount of metallocene compound supported is generally between0.1 and 5% by weight expressed as metal.

[0046] The atomic ratio of Mg to transition metal is generally between10 and 200; it can, however, be less and reach values of 1 or even lesswhen the Mg halide is supported on an inert support.

[0047] The metallocene compounds are sparingly soluble in hydrocarbons(the hydrocarbon solvents most used are benzene, toluene, hexane,heptane and the like). Their solubility increases considerably if thesolvent contains a dissolved alkyl-Al compound such as triethyl-Al,triisobutyl-Al or a polyalkylalumoxane in particular MAO(polymethyl-alumoxane) in molar ratios with the metallocene compoundgreater than 2 and preferably between 5 and 100.

[0048] Impregnation of the support starting from the solution mentionedabove makes it possible to obtain particularly active catalysts (theactivity is greater than that of the catalysts that can be obtained fromsolutions of the metallocene compound that do not contain the alkyl-Alcompound or MAO).

[0049] The metallocene compounds that can be used are selected from thecompounds of a transition metal M selected from Ti, V, Zr and Hfcontaining at least one metal-π bond, and comprising preferably at leastone ligand L coordinated on the metal M possessing a mono- or polycyclicstructure containing conjugated π electrons.

[0050] The said compound of Ti, V, Zr or Hf is preferably selected fromcomponents possessing the structure:.

Cp^(I)MR¹ _(a)R² _(b)R³ _(c)  (I)

Cp^(I)1Cp^(II)MR¹ _(a)R² _(b)  (II)

(Cp^(I)—A_(c)—Cp^(II)) M¹R¹ _(a)R² _(b)  (III)

[0051] in which M is Ti, V, Zr or Hf; Cp^(I) and Cp^(II), identical ordifferent, are cyclopentadienyl groups, including substituted ones; twoor more substituents on the said cyclopentadienyl groups can form one ormore rings possessing from 4 to 6 carbon atoms; R¹, R² and R³, identicalor different, are atoms of hydrogen, halogen, an alkyl or alkoxyl groupwith 1-20 carbon atoms, aryl, alkaryl or aralkyl with 6-20 carbon atoms,an acyloxy group with 1-20 carbon atoms, an allyl group, a substituentcontaining a silicon atom; A is an alkenyl bridge or one with structureselected from:

[0052] in which M₁ is Si, Ge, or Sn; R₁ and R₂, identical or different,are alkyl groups with 1-4 carbon atoms or aryl groups with 6-10 carbonatoms; a, b, c are, independently, integers from 0 to 4; e is an integerfrom 1 to 6 and two or more of the radicals R¹, R² and R³ can form aring. In the case when the Cp group is substituted, the substituent ispreferably an alkyl group with 1-20 carbon atoms.

[0053] Representative compounds that have formula (I) include:(Me₅Cp)MMe₃, (Me₅Cp)M(OMe)₃, (Me₅Cp)MCl₃, (Cp)MCl₃, (Cp)MMe₃,(MeCp)MMe₃, (Me₃Cp)MMe₃, (Me₄Cp)MCl₃, (Ind)MBenz₃, (H₄Ind)MBenz₃,(Cp)MBu₃.

[0054] Representative compounds that have formula (II) include:(Cp)₂MMe₂, (Cp)₂MPh₂, (Cp)₂MEt₂, (Cp)₂MCl₂, (Cp)₂M(OMe)₂, (Cp)₂M(OMe)Cl,(MeCp)₂MCl₂, (Me₅Cp)₂MCl₂, (Me₅Cp)₂MMe₂, (Me₅Cp)₂MMeCl, (Cp)(Me₅Cp)MCl₂,(1-MeFlu)₂MCl₂, (BuCp)₂MCl₂, (Me₃Cp)₂MCl₂, (Me₄Cp)₂MCl₂,(Me₅Cp)₂M(OMe)₂, (Me₅Cp)₂M(OH)Cl, (Me₅Cp)₂M(OH)₂, (Me₅Cp)₂M(C₆H₅)₂,(Me₅Cp)₂M(CH₃)Cl, (EtMe₄Cp)₂MCl₂, [(C₆H₅)Me₄Cp]₂MCl₂, (Et₅Cp)₂MCl₂,(Me₅Cp)₂M(C₆H₅)Cl, (Ind)₂MCl₂, (Ind)₂MMe₂, (H₄Ind)₂MCl₂, (H₄Ind)₂MMe₂,{[Si(CH₃)₃]Cp}₂MCl₂, {[Si(CH₃)₃]₂Cp}₂MCl₂, (Me₄Cp)(Me₅Cp)MCl₂.

[0055] Representative compounds of formula (III) include:C₂H₄(Ind)₂MCl₂, C₂H₄(Ind)₂MMe₂, C₂H₄(H₄Ind)₂MCl₂, C₂H₄(H₄Ind)₂MMe₂,Me₂Si(Me₄Cp)₂MCl₂, Me₂Si(Me₄Cp)₂MMe₂, Me₂SiCp₂MCl₂, Me₂SiCp₂MMe₂,Me₂Si(Me₄Cp)₂MMeOMe, Me₂Si(Flu)₂MCl₂, Me₂Si(2-Et-5-iPrCp)₂MCl₂,Me₂Si(H₄Ind)₂MCl₂, Me₂Si(H₄Flu)₂MCl₂, Me₂SiCH₂(Ind)₂MCl₂,Me₂Si(2-Me-H₄Ind)MCl₂, Me₂Si(2-MeInd)₂MCl₂, Me₂Si(2-Et-5-iPr-Cp)₂MCl₂,Me₂Si(2-Me-5-EtCp)₂MCl₂, Me₂Si(2-Me-5-Me-Cp)₂MCl₂,Me₂Si(2Me-4,5-benzoindenyl)₂MCl₂, Me₂Si(4,5-benzoindenyl)₂MCl₂,Me₂Si(2-EtInd)₂MCl₂, Me₂Si(2-iPr-Ind)₂MCl₂, Me₂Si(2-t-butyl-Ind)MCl₂,Me₂Si(3-t-butyl-5-MeCp)₂MCl₂, Me₂Si(3-t-butyl-5-MeCp)₂MMe₂,Me₂Si(2-MeInd)₂MCl₂, C₂H₄(2-Me-4,5-benzoindenyl)₂MCl₂, Me₂C(Flu)CpMCl₂,Ph₂Si(Ind)₂MCl₂, Ph(Me)Si(Ind)₂MCl₂, C₂H₄(H₄Ind)M(NMe₂)OMe,isopropylidene-(3-t-butyl-Cp)(Flu)MCl₂, Me₂C(Me₄Cp)(MeCp)MCl₂,MeSi(Ind)₂MCl₂, Me₂Si(Ind)₂MMe₂, Me₂Si(Me₄Cp)₂MCl(OEt),C₂H₄(Ind)₂M(NMe₂)₂, C₂H₄(Me₄Cp)₂MCl₂, C₂Me₄(Ind)₂MCl₂,Me₂Si(3-Me-Ind)₂MCl₂, C₂H₄(2-Me-Ind)₂MCl₂, C₂H₄(3-Me-Ind)₂MCl₂,C₂H₄(4,7-Me₂-Ind)₂MCl₂, C₂H₄(5,6-Me₂-Ind)₂MCl₂, C₂H₄(2,4,7-Me₃Ind)₂MCl₂,C₂H₄(3,4,7-Me₃Ind)₂MCl₂, C₂H₄(2-Me-H₄Ind)₂MCl₂,C₂H₄(4,7-Me₂-H₄Ind)₂MCl₂, C₂H₄(2,4,7-Me₃-H₄Ind)₂MCl₂,Me₂Si(4,7-Me₂-Ind)₂MCl₂, Me₂Si(5,6-Me₂-Ind)₂MCl₂,Me₂Si(2,4,7-Me₃-H₄Ind)₂MCl₂.

[0056] In the simplified formulae given above, the symbols have thefollowing meanings: Me=methyl, Et=ethyl, iPr=isopropyl, Bu=butyl,Ph=phenyl, Cp=cyclopentadienyl, Ind=indenyl,H₄Ind=4,5,6,7-tetrahydroindenyl, Flu=fluorenyl, Benz=benzyl, M=Ti, Zr orHf, preferably Zr.

[0057] Compounds of the type Me₂Si(2-Me-Ind)₂ZrCl₂ andMe₂Si(2-Me-H₄Ind)ZrCl₂ and their methods of preparation are describedrespectively in European Applications EP-A-485822 and 485820 whosedescription is included here for reference.

[0058] Compounds of the type Me₂Si(3-t-butyl-5-MeCp)₂ZrCl₂ and of thetype Me₂Si(2-Me-4,5-benzoindenyl)ZrCl₂ and their method of preparationare described respectively in U.S. Pat. No. 5,132,262 and in PatentApplication EP-A-549900 whose description is included here forreference.

[0059] The components of the invention form, with alkyl-Al compounds orwith polyalkyl-alumoxane compounds or their mixtures, catalysts thatpossess very high activity relative to the Mg halide.

[0060] The alkyl-Al compound is generally selected from compounds offormula AlR₃, in which R is an alkyl that has 1-12 carbon atoms, and thealumoxane compounds containing the repeating unit —(R⁴)AlO—, in which R⁴is an alkyl radical containing from 1 to 6 carbon atoms, and the saidalumoxane compounds contain from 2 to 50 repeating units that have theformula described above. Typical examples of compounds that have theformula AlR₃ are trimethyl-Al, triethyl-Al, triisobutyl-Al,tri-n-butyl-Al, trihexyl-Al, trioctyl-Al. Among the alumoxane compounds,use of MAO is preferable. Mixtures of alkyl-Al compounds, preferablytriisobutyl-Al, and alumoxane compounds, preferably MAO, are also usedadvantageously.

[0061] When the transition metal compound containing at least one M-πbond is of the type described in formulae (II) and (III), the compoundsobtained from the reaction between AlR₃ and H₂O in molar ratios between0.01 and 0.5 can be used advantageously.

[0062] In general the alkyl-Al compound is used in molar ratios relativeto the transition metal between 10 and 5000, preferably between 100 and4000, and more preferably between 500 and 2000.

[0063] The catalysts of the invention can be used for (co)polymerizingCH₂═CHR olefins, in which R is hydrogen or an alkyl radical with 1-10carbon atoms or an aryl.

[0064] They are used in particular for polymerizing ethylene and itsmixtures with α-olefins of the type stated above in which R is an alkylradical.

[0065] The catalysts, particularly those obtained from compounds of thetype C₂H₄(Ind)₂ZrCl₂, C₂H₄(H₄Ind)ZrCl₂ and Me₂Si(Me₄Cp)₂ZrCl₂, aresuitable for producing LLDPE (copolymers of ethylene containing smallerproportions, generally below 20 mol %, of α-olefin C₃-C₁₂) characterizedby relatively low density values in relation to the content of α-olefin,with reduced solubility in xylene at room temperature (below approx. 10%by weight) and with molecular weight distribution Mw/Mn between about2.5 and 5.

[0066] The polypropylenes that can be obtained with the catalysts usinga chiral metallocene compound are characterized by increasedstereoregularity, high molecular weights that are easily controllable,and high degree of crystallinity.

[0067] The chiral metallocene compounds that can be used are for exampleof the type described in European Application EP-A-485823, EP-A-485820,EP-A-519237, and U.S. Pat. Nos. 5,132,262, and 5,162,278.

[0068] The following examples are given for the purpose of illustratingbut not limiting the invention. The properties stated are determined inaccordance with the following methods:

[0069] Porosity and surface area (BET): are determined according to BETmethods (apparatus used: SORPTOMATIC 1800 from Carlo Erba). The porosityis calculated from the integral pore distribution curve in function ofthe pores themselves.

[0070] Porosity and surface area with mercury: are determined byimmersing a known quantity of the sample in a known quantity of mercuryinside a dilatometer and then gradually increasing the pressure of themercury hydraulically. The pressure of introduction of the mercury intothe pores is a function of their diameter. Measurement is effected usinga “Porosimeter 2000 series” porosimeter from Carlo Erba. The porosity,pore distribution and surface area are calculated from data on thedecrease of volume of the mercury and from the values of the appliedpressure.

[0071] The porosity and surface areas stated in the descriptions and inthe examples are referred to pore dimensions up to 10000 Å.

[0072] Size of the catalyst particles: is determined by a method basedon the principle of optical diffraction of monochromatic laser lightwith the “Malvern Instr. 2600” apparatus. The average size is stated asP50.

[0073] Melt Index E (MIE): determined according to ASTM-D 1238, methodE.

[0074] Melt Index F (MIF): determined according to ASTM-D 1238, methodF.

[0075] Ratio of degrees (F/E): ratio between Melt Index F and Melt IndexE.

[0076] Flowability: is the time taken for 100 g of polymer to flowthrough a funnel whose discharge hole has a diameter of 1.25 cm andwhose walls are inclined at 20° to the vertical.

[0077] Apparent density: DIN 53194.

[0078] Morphology and granulometric distribution of the particles ofpolymer: ASTM-D 1921-63.

[0079] Fraction soluble in xylene: measured by dissolving the polymer inboiling xylene and determining the insoluble residue after cooling to25° C.

[0080] Content of comonomer: percentage by weight of comonomerdetermined from IR spectrum.

[0081] Density: ASTM-D 792.

[0082] Average size of MgCl₂ crystallites [D(110)]: is determined frommeasurement of the width at half-height of the (110) diffraction linethat appears in the X-ray spectrum of the magnesium halide, applyingScherrer's equation:

D(110)=(K·1.542·57.3)/(B−b)cos θ,

[0083] in which:

[0084] K=constant (1.83 in the case of magnesium chloride);

[0085] B=half-width (in degrees) of the (110) diffraction line;

[0086] b=instrumental broadening;

[0087] θ=Bragg angle.

[0088] In the case of magnesium chloride, the (110) diffraction lineappears at an angle 2θ of 50.2°.

EXAMPLES Example 1 Preparation of the Support

[0089] A spherical adduct MgCl₂.3EtOH was prepared according to theprocedure described in Example 2 of Patent U.S. Pat. No. 4,399,054,operating at 3000 rpm instead of at 10000 rpm. The adduct was partiallydealcoholized by heating in a stream of nitrogen at temperaturesincreasing from 30° C. to 180° C., until an adduct containing 10% byweight of EtOH was obtained.

Preparation of the Metallocene/Triisobutylaluminium Solution

[0090] A reactor with capacity of 1000 cm³, equipped with an anchorstirrer and treated with N₂, was fed with 382.5 cm³ oftriisobutylaluminium (TIBAL) in hexane solution (100 g/liter) and 14.25g of ethylene-bis-indenyl zirconium dichloride (EBI). The system wasstirred in N₂ atmosphere at 20° C. for 1 hour. A clear solution wasobtained at the end of this period.

Preparation of the Catalyst

[0091] A reactor with capacity of 1000 cm³, equipped with an anchorstirrer, and treated with N₂ at 90° C. for 3 hours, was loaded, at 20°C. in a nitrogen atmosphere, with 600 cm³ of heptane and 60 g of thesupport prepared previously. While stirring at 20° C., 238 cm³ of hexanesolution of TIBAL (100 g/l) were introduced in 30 minutes. The mixturewas heated to 80° C. in 1 hour and kept at this temperature for 2 hours.The mixture was then cooled to 20° C. and 62.5 cm³ of the TIBAL/EBIsolution previously prepared were added. The system was heated to 60° C.in 30 minutes and kept at this temperature for 2 hours. At the end ofthis period 3 washings with hexane were effected at 60° C., removing thesolvent by evaporation under vacuum at maximum temperature of about 60°C. Approximately 62 g of spherical catalyst, with the followingcharacteristics, was obtained: Mg=21.33%; Cl=66.59%; Al=0.96%; Zr=0.41%;EtO=0.3%;

[0092] Surface area (Hg) 70.9 m²/g

[0093] Porosity (Hg) 1.041 cm³/g

[0094] Surface area (BET) 61.9 m²/g

[0095] Porosity (BET) 0.687 cm³/g

Polymerization (LLDPE)

[0096] 0.05 g of the catalyst described above and 0.42 g of methylalumoxane (MAO) in 100 cm³ of toluene were precontacted for 5 minutes at20° C. in a glass flask, which had been treated with N₂ at 90° C. for 3hours. The whole was placed in a 4-liter steel autoclave, equipped withan anchor stirrer, and treated with N₂ at 90° C. for 3 hours, containing800 g of propane at 30° C. The autoclave was heated to 75° C. and 0.1bar of H₂ was introduced and then, simultaneously, 7 bar of ethylene and100 g of 1-butene. Polymerization was carried out for 1 hour, keepingthe temperature and the ethylene pressure constant. 115 g ofethylene-butene copolymer was obtained (g copolymer per g catalyst=2300;kg copolymer per g Zr=545) with the following characteristics: MIE=0.84;F/E=49.16; η=1.35; density=0.914; butene=10.1%; insoluble inxylene=97.42%.

Polymerization (HDPE)

[0097] 0.42 g of MAO and 0.05 g of the catalyst described above in 100cm³ of toluene were precontacted for 5 minutes at 30° C. in a glassflask that had been treated with N₂ at 90° C. for 3 hours. The whole wasthen placed in a 4-liter steel autoclave, equipped with an anchorstirrer and treated with N₂ at 90° C. for 3 hours, containing 1.6 litersof hexane at 20° C. The autoclave was heated to 75° C. and 7 bar ofethylene and 0.25 bar of H₂ were introduced. Polymerization was effectedfor 1 hour, keeping the ethylene temperature and pressure constant.Polymerization was stopped by instantaneous degassing of the autoclaveand, after cooling to 20° C., the polymer slurry was discharged and wasdried at 80° C. in nitrogen atmosphere. 100 g of polyethylene wereobtained (2000 g polyethylene/g catalyst; 492 kg polyethylene/g Zr),with the following characteristics: MIE=12.9; F/E=22.5; η=0.7.

Example 2 Preparation of the Metallocene/Alumoxane Solution

[0098] A 1000 cm³ reactor, equipped with an anchor stirrer and treatedwith N₂, was loaded with 600 cm³ of toluene, 18.87 g ofpolymethyl-alumoxane (MAO) and 8.46 g of EBI. The system was stirred inan atmosphere of N₂ at 20° C. for 1 hour. A clear solution was obtainedat the end of this period.

Preparation of the Catalyst

[0099] A 1000 cm³ reactor, equipped with an-anchor stirrer and treatedwith N₂ at 90° C. for 3 hours, was fed, in an atmosphere of N₂ at 20°C., with 600 cm³ of heptane and 60 g of support prepared according tothe methodology in Example 1. While stirring at 20° C., 86.4 cm³ ofsolution of trimethylaluminium (TMA) in hexane (100 g/liter) wereintroduced in 30 minutes. In 1 hour the system was heated to 80° C. andwas maintained at this temperature for 2 hours. The mixture was thencooled to 20° C. and 62.5 cm³ of the MAO/EBI solution previouslyprepared were introduced. The system was heated to 60° C. in 30 minutesand was kept at this temperature for 2 hours. At the end of this period,3 washings with hexane were effected at 60° C., removing the solvent byevaporation under vacuum at maximum temperature of about 60° C. 65 g ofspherical catalyst with the following characteristics was obtained:Mg=19.3%; Cl=61.5%; Al=3.87%; Zr=0.33%; OEt=4.3%.

Polymerization (HDPE)

[0100] 0.05 g of the catalyst described above was precontacted with MAO(0.42 g) in the conditions of Example 2. Then ethylene was polymerizedin the conditions in Example 2, obtaining 100 g of polymer (2000 gpolyethylene/g cat; 575 kg polymer/g Zr) with the followingcharacteristics: MIE=9.5; F/E=12.68; η=0.66.

Example 3 Preparation of the Metallocene/Alumoxane Solution

[0101] Preparation was effected in the same conditions as Example 2 butusing 47.18 g of MAO instead of 18.87 g.

Preparation of the Catalyst

[0102] The catalyst was prepared following the procedure described inExample 2, using 166.6 cm³ of the metallocene-alumoxane solutiondescribed above. Once the solvent had been removed by evaporation,approx. 65 g of spherical catalyst with the following characteristicswere obtained: Mg=18.41; Cl=57.5; Al=5.56; Zr=0.42.

Polymerization (HDPE)

[0103] 0.05 g of the catalyst described above was precontacted andpolymerized in the same conditions as in Example 1, using 0.1 bar of H₂instead of 0.25 bar. 80 g of polyethylene were obtained (1600 gpolyethylene/g cat; 381 kg polyethylene/g Zr), with the followingcharacteristics: MIE=5.9; F/E=17.9; η=0.77.

Example 4 Preparation of the Support

[0104] A spherical adduct MgCl₂.3EtOH was prepared following theprocedure described in Example 2 of Patent U.S. Pat. No. 4,399,054,operating at 3000 rpm instead of at 10000 rpm. The adduct was partiallydealcoholized by heating in a stream of nitrogen at temperaturesincreasing from 30° C. to 180° C., until an adduct containing 35% byweight of EtOH was obtained.

Preparation of the Metallocene/Triisobutylaluminium Solution

[0105] A reactor with capacity of 1000 cm³, equipped with an anchorstirrer and treated with N₂, was loaded with 382.5 cm³ oftriisobutylaluminium (TIBAL) in hexane solution (100 g/liter) and 14.25g of ethylene-bis-indenyl zirconium dichloride (EBI). The system wasstirred in an atmosphere of N₂ at 20° C. for 1 hour. A clear solutionwas obtained at the end of this period.

Preparation of the Catalyst

[0106] A reactor with capacity of 3000 cm³, equipped with an anchorstirrer and treated with N₂ at 90° C. for 3 hours, was loaded, at 20° C.in an atmosphere of nitrogen, with 600 cm³ of heptane and 60 g of thesupport previously prepared. While stirring at 20° C., 900 cm³ of hexanesolution of TIBAL (100 g/l) were introduced in 30 minutes. The mixturewas heated to 80° C. in 1 hour and was maintained at this temperaturefor 2 hours. The mixture was then cooled to 20° C. and 62.5 cm³ of theTIBAL/EBI solution prepared previously were introduced. The system washeated to 60° C. in 30 minutes and was maintained at this temperaturefor 2 hours. At the end of this period, 3 washings were effected withhexane at 60° C., removing the solvent by evaporation under vacuum atthe maximum temperature of about 60° C. After drying, about 65 g ofcatalyst with the following characteristics were obtained: Zr=0.6%;Mg=15.3%; Cl=48.2%; Al=4.6%;

[0107] Surface area (Hg) 24.1 m²/g

[0108] Porosity (Hg) 0.359 cm³/g

[0109] Surface area (BET) 129.2 m²/g

[0110] Porosity (BET) 0.837 cm³/g

Polymerization (LLDPE)

[0111] 0.05 g of the catalyst described above was precontacted andpolymerized following the same procedure as in Example 1, using 0.25 barof H₂ instead of 0.1 bar. At the end, 170 g of ethylene-butene copolymerwere obtained (3400 g copolymer/g cat; 564 kg copolymer/g Zr) with thefollowing characteristics: MIE=4.76; F/E=32.2; η=1.1; density=0.9135;butene=10.5%; insoluble in xylene=95%.

Example 5 Preparation of the Catalyst

[0112] A reactor with capacity of 1000 cm³, equipped with an anchorstirrer and treated with N₂ at 90° for 3 hours, was loaded, in anatmosphere of N₂ at 20° C., with 500 cm³ of toluene and 100 g of thesupport prepared according to the procedure in Example 4. While stirringat 20° C., 55 g of trimethylaluminium (heptane solution 100 g/l) wereintroduced, and then the mixture was heated at 105° C. for 3 hours. Atthe end the temperature was lowered to 20° C. and 102 cm³ of theTIBAL/EBI solution prepared according to the procedure in Example 4 wereintroduced, then the whole was heated at 80° C. for 2 hours. Afterremoving the solvent by evaporation, about 120 g of spherical catalystwith the following characteristics were obtained: Zr=0.6%; Mg=16.5%;Cl=49.2%; Al=6.7%;

[0113] Surface area (Hg) 33.8 m²/g

[0114] Porosity (Hg) 0.495 cm³/g

[0115] Surface area (BET) 171.3 m²/g

[0116] Porosity (BET) 0.291 cm³/g

Polymerization (HDPE)

[0117] 0.05 g of the catalyst described above was precontacted andpolymerized in the same conditions of Example 1, using 0.1 bar of H₂instead of 0.25 bar. 115 g of polyethylene (2300 g polyethylene/g cat)with the following characteristics were obtained: MIE=0.78; F/E=66.8.

Example 6 Preparation of the Support

[0118] A spherical adduct MgCl₂.3EtOH was prepared following theprocedure described in Example 2 of Patent U.S. Pat. No. 4,399,054,operating at 3000 rpm instead of at 10000 rpm. The adduct was partiallydealcoholized by heating in a stream of nitrogen at temperaturesincreasing from 30° C. to 180° C., until an adduct containing 45% byweight of EtOH was obtained. 2360 g of spherical adduct thus obtainedwere loaded into a 30-liter reactor containing 18 liters of hexane.While stirring at room temperature, 1315 g of AlEt₃ in hexane solution(100 g/liter) were introduced. The mixture was heated to 60° C. in 60minutes and was maintained at this temperature for 60 minutes. Theliquid phase was separated and 15 liters of hexane were introduced. Thetreatment with AlEt₃ was repeated twice more operating under the sameconditions. At the end, the spherical support obtained was washed 5times with hexane and was dried under vacuum.

Preparation of the Catalyst

[0119] A 1000 cm³ reactor, equipped with an anchor stirrer and treatedwith N₂ at 90° C. for 3 hours, was loaded, in an atmosphere of nitrogenat 20°, with 500 cm³ of toluene and 60 g of support. 53.68 cm³ of themetallocene/TIBAL solution prepared according to the procedure inExample 4 were then introduced, stirring continuously for 2 hours at 20°C. At the end, four washings were effected with hexane at 20° C.,removing the solvent by evaporation under vacuum. About 62 g ofspherical catalyst with the following characteristics were obtained:Zr=1.1%; Mg=16.6%; Cl=55.3%; Al=3.6%; OEt=3.2%;

[0120] Surface area (Hg) 38.3 m²/g

[0121] Porosity (Hg) 0.604 cm³/g

[0122] Surface area (BET) 298.9 m²/g

[0123] Porosity (BET) 0.327 cm³/g

Polymerization (LLDPE)

[0124] 0.05 g of the catalyst described above was polymerized using thesame procedure as in Example 1, obtaining 160 g of ethylene-butenecopolymer (3200 g copolymer/g cat; 290 kg copolymer/g Zr) with thefollowing characteristics: MIE=1.28; F/E=50.7; butene=10.5%; η=1.37;insoluble in xylene=95.32%; density=0.9122.

[0125] The test was repeated using 1.45 g of TIBAL instead of 0.42 g ofMAO and 1 bar of H₂ instead of 0.1. 10 g of copolymer was obtained (200g copolymer/g cat; 17.3 kg copolymer/g Zr) with η=0.3.

Example 7 Preparation of the Catalyst

[0126] The catalyst was prepared according to the procedure of Example6, except that the four washings with hexane were not effected at theend of the preparation. About 63 g of spherical catalyst were obtained,with the following characteristics: Zr=1.11%; Mg=13%; Cl=44.8%; Al=3.9%;OEt=6.4%;

[0127] Surface area (Hg) 19.7 m²/g

[0128] Porosity (Hg) 0.476 cm³/g

[0129] Surface area (BET) 230.2 m^(2/)g

[0130] Porosity (BET) 0.197 cm³/g

Polymerization (LLDPE)

[0131] 0.05 g of the catalyst described above was polymerized accordingto the methodology described in Example 1, using 1 bar of H₂ instead of0.1 and 150 g of butene instead of 100. 330 g of ethylene-butenecopolymer were obtained (6600 g copolymer/g cat; 597 kg copolymer/g Zr),with the following characteristics: MIE=16.3; F/E=34.6; η=0.76;density=0.9097; Mw/Mn=3.7.

Example 8 Preparation of the Catalyst

[0132] A reactor with capacity of 1000 cm³, equipped with an anchorstirrer and treated with N₂ at 90° C. for 3 hours, was loaded, in anatmosphere of N₂ at 20° C., with 600 cm³ of heptane and 60 g of supportprepared according to the methods in Example 6. While stirring at 20°C., 86.4 cm³ of solution of trimethyl-aluminium (TMA) in hexane (100g/liter) were introduced in 30 minutes. The system was heated to 80° C.in 1 hour and was maintained at this temperature for 2 hours. Thesolution was than cooled to 20° C. and 272 cm³ of EBI/MAO solutionprepared according to the procedure of Example 3 were introduced. Themixture was heated to 60° C. in 30 minutes and was maintained at thistemperature for 2 hours. At the end of this period the solvent wasremoved by evaporation under vacuum at maximum temperature of about 60°C. for about 3 hours. About 63 g of spherical catalyst with thefollowing characteristics were obtained: Zr=0.8%; Mg=12.6%; Cl=40%;Al=9.3%.

Polymerization (LLDPE)

[0133] 0.05 g of the catalyst described above was used for thepreparation of an ethylene-butene copolymer according to the procedurein Example 1, using 1.45 g of TIBAL instead of 0.42 g of MAO. At theend, 45 g of copolymer were obtained (900 g copolymer/g cat; 110 kgcopolymer/g Zr), with the following characteristics: MIE=8.34;F/E=28.91; η=1.15; insoluble in xylene=81.5%; density=0.905.

Example 9 Preparation of Support

[0134] The support was prepared according to the procedure described inExample 1.

Preparation of the Catalyst

[0135] In a 1000 cm³ reactor, equipped with a mechanical stirrer andpretreated with N₂ at 90° C. for 3 hours, 600 cm³ of hexane and 120 g ofthe above described support were fed at 20° C. under a nitrogenatmosphere; 16.2 g of isoamyl ether was then added over 30 minutes andthe system was heated to 50° C. and kept at this temperature for 1 hour.At the end of this period it was cooled to 20° C., 5 g of ethylenebisindenyl zirconium chloride was added and the whole was kept stirredfor 15 minutes. Then, 15.7 g of diethyl aluminium monochloride (100 g/lsolution in hexane) was added and the mixture was heated to 40° C.maintaining at this temperature for 1 hour. After this period, themixture was cooled to 20° C., the solid was allowed to settle and theliquid phase was removed. 600 cm³ of hexane and 15.7 g of AlEt₂Cl werefed and the above described treatment was repeated. Finally the productwas washed three times with 200 cm³ of hexane at 60° and three timeswith 200 cm³ of hexane at 20°, obtaining 102 g of spherical catalystcomponent having the following characteristics: Mg=21.4%; Cl=65.79%;Al=0.3%; Zr=0.67%; isoamyl ether=2.0%; EtO=3.8%.

Polymerization (HDPE)

[0136] The so obtained catalyst was used to prepare HDPE according tothe process described in Example 2. 240 g of polymer were obtained (4813g PE/g catalyst; 780 Kg PE/g Zr) having the following characteristics:MIE=1.02; F/E=62; η=1.08; Mw/Mn=2.9.

Example 10 Preparation of Support

[0137] The support was prepared according to the procedure described inExample 6.

Preparation of the Metallocene/Triisobutylaluminium Solution

[0138] In a 1000 cm³ reactor, equipped with mechanical stirrer andpurged with nitrogen, 620 cm³ of triisobutyl aluminium in hexanesolution (100 g/l) and 42 g of ethylene-bis-4,7-dimethylindenylzirconium dichloride (EBDMI) were fed. The reaction was carried out asdescribed in Example 1.

Preparation of the Catalyst

[0139] Into a previously purged 2 l reactor, 250 cm³ of heptane and 35 gof the above described support were fed. The mixture was cooled to 0° C.and 505 cm³ of TIBAL (100 g/l solution in hexane) were added; the wholewas heated to 60° C. for 1 hour and subsequently cooled to 20° C. 31 cm³of the above described EBDMI/TIBAL solution was fed and the mixture washeated to 70° C. for 2 hours, after which it was cooled to 20° C.; thesolid was allowed to settle and the liquid was siphoned. After dryingunder vacuum at 50° C., about 30 g of spherical catalyst was obtained,having the following characteristics: Mg=15.95%; Cl=54.75%; Al=3.2%;Zr=0.98%; EtO=7.0%.

Polymerization (LLDPE)

[0140] The so obtained catalyst was used in the preparation of LLDPEaccording to example 1, using 1.45 g of TIBAL instead of 0.42 g of MAO.100 g of copolymer was obtained (g copolymer/g cat=2000; Kg ofcopolymer/g Zr=200) having the following characteristics: MIE=0.48;F/E=45.83; density=0.919; Insolubility in xylene=98.51%.

Example 11 Preparation of Support

[0141] The support was prepared according to the procedure described inExample 8.

Preparation of the Metallocene/Methylaluminoxane Solution

[0142] Into a previously purged one liter reactor, 600 cm³ of toluene,76.5 g of methylaluminoxane and 15.6 g of EBDMI were fed; the system waskept under stirring at 20° C. for 2 hours.

Preparation of the Catalyst

[0143] Into a previously purged 1 liter reactor, 200 cm³ of toluene and100 g of the above described support were added; subsequently 200 cm³ ofthe above described metallocene/MAO solution was added and the systemwas heated to 40° C. and kept stirred at this temperature for 2 hours.Finally the solid was allowed to settle and the liquid was removed bysyphoning. The obtained sold was then washed four times with 200 cm³ ofhexane at 20° C. and subsequently dried. 125 g of spherical catalyst wasobtained having the following characteristics: Cl=45.35%; Mg=16.25%;Al=7.1%; Zr=0.45%.

Polymerization (LLDPE)

[0144] The above described catalyst was used to prepare LLDPE accordingto the procedure of example 10. 37.7 g of polymer were obtained (754 gcopolymer/g catalyst; 167 Kg of copolymer/g di Zr) with the followingcharacteristics: MIE=0.4; F/E=46.25; Insolubility in xylene=97%; η=1.77;Density=0.913.

1. A component of catalysts for the polymerization of olefins comprising a compound of a transition metal M selected among Ti, V, Zr and Hf containing at least one M-π bond, and a halide of Mg, characterized by surface area (BET) greater than about 50 m²/g, porosity (BET) greater than 0.15 cm³/g and porosity (Hg) greater than 0.3 cm³/g, with the proviso that when the surface area is less than about 150 m²/g, the porosity (Hg) is less than about 1.5 cm³/g.
 2. A component according to claim 1 , having surface area greater than 150 m²/g and porosity (BET) greater than 0.2 cm³/g.
 3. A component according to claim 1 , having surface area less than 150 m²/g and porosity (Hg) between 0.5 and 1.2 cm³/g.
 4. A component according to claim 1 , wherein more than 40% of the porosity (BET) is due to pores with radius greater than 300 Å.
 5. A component according to claim 1 , wherein more than 50% of the porosity (BET) is due to pores with radius between 600 Å and 1000 Å.
 6. A component according to claim 1 in the form of spheroidal particles with size smaller than 150 microns.
 7. A component according to claim 1 obtained by supporting a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-π bond, on a halide of Mg or on a support containing a halide of Mg that has surface area between 200 and 800 m²/g and porosity (BET) greater than 0.3 cm³/g and porosity (Hg) greater than 0.3 cm³/g.
 8. A component according to claim 7 , wherein the halide of Mg is in the form of spheroidal particles with size smaller than 150 microns.
 9. A component according to claim 7 , wherein the halide of Mg is supported on an inert support selected from silica, alumina, silica-alumina possessing surface area between 300 and 600 m²/g and porosity (BET) greater than 0.5 cm³/g and partially crosslinked polystyrene with surface area between 100 and 500 m²/g and porosity (BET) greater than 0.5 cm³/g.
 10. A component according to claim 8 , wherein the halide of Mg is obtained from spherulized MgX₂.alcohol adducts that are then reacted with an alkyl-Al compound to remove the alcohol.
 11. A component according to claim 10 , wherein the Mg halide is Mg chloride obtained from MgCl₂.3ROH adducts, in which R is an alkyl radical with 1-8 carbon atoms, which are submitted to partial dealcoholizing and then reacted with the alkyl-Al compound.
 12. A component according to claim 1 , wherein the transition metal compound contains at least one ligand L coordinated on the metal M, which has a mono- or polycyclic structure containing conjugated π electrons.
 13. A component according to claim 12 , wherein the transition metal compound is selected from compounds having the structure: Cp^(I)MR¹ _(a)R² _(b)R³ _(c)  (I) Cp^(I)1Cp^(II)MR¹ _(a)R² _(b)  (II) (Cp^(I)—A_(c)—Cp^(II))MR¹ _(a)R² _(b)  (III) in which M is Ti, V, Zr or Hf; CpI and Cp^(II), identical or different, are cyclopentadienyl groups, including substituted ones; two or more substituents on the said cyclopentadienyl groups can form one or more rings possessing from 4 to 6 carbon atoms; R¹, R² and R³, identical or different, are atoms of hydrogen, halogen, an alkyl or alkoxyl group with 1-20 carbon atoms, aryl, alkaryl or aralkyl with 6-20 carbon atoms, an acyloxy group with 1-20 carbon atoms, an allyl group, a substituent containing a silicon atom; A is an alkenyl bridge or one with structure selected from:

═AlR₁, —Ge—, —Sn—, —O—, —S—, ═SO, ═SO₂, ═NR₁, ═PR₁, ═P(O)R₁, in which M₁ is Si, Ge, or Sn; R₁ and R₂, identical or different, are alkyl groups with 1-4 carbon atoms or aryl groups with 6-10 carbon atoms; a, b, c are, independently, integers from 0 to 4; e is an integer from 0 to 6 and two or more of the radicals R¹, R² and R³ can form a ring.
 14. A component according to claim 12 , wherein the transition metal compound is selected from compounds that have the structure: (Me₅Cp)MMe₃, (Me₅Cp)M(OMe)₃, (Me₅Cp)MCl₃, (Cp)MCl₃, (Cp)MMe₃, (MeCp)MMe₃, (Me₃Cp)MMe₃, (Me₄Cp)MCl₃, (Ind)MBenz₃, (H₄Ind)MBenz₃, (Cp)MBu₃.
 15. A component according to claim 12 , wherein the transition metal compound is selected from compounds that have the structure: (Cp)₂MMe₂, (Cp)₂MPh₂, (Cp)₂MEt₂, (Cp)₂MCl₂, (Cp)₂M(OMe)₂, (Cp)₂M(OMe)Cl, (MeCp)₂MCl₂, (Me₅Cp)₂MCl₂, (Me₅Cp)₂MMe₂, (Me₅Cp)₂MMeCl, (Cp)(Me₅Cp)MCl₂, (1-MeFlu)₂MCl₂, (BuCp)₂MCl₂, (Me₃Cp)₂MCl₂, (Me₄Cp)₂MCl₂, (Me₅Cp)₂M(OMe)₂, (Me₅Cp)₂M(OH)Cl, (Me₅Cp)₂M(OH)₂, (Me₅Cp)₂M(C₆H₅)₂, (Me₅Cp)₂M(CH₃)Cl, (EtMe₄Cp)₂MCl₂, [(C₆H₅)Me₄Cp]₂MCl₂, (Et₅Cp)₂MCl₂, (Me₅Cp)₂M(C₆H₅)Cl, (Ind)₂MCl₂, (Ind)₂MMe₂, (H₄Ind)₂MCl₂, (H₄Ind)₂MMe₂, {[Si(CH₃)₃]Cp}₂MCl₂, {[Si(CH₃)₃]₂Cp}₂MCl₂, (Me₄Cp)(Me₅Cp)MCl₂.
 16. A component according to claim 12 , wherein the transition metal compound is selected from compounds that have the structure: C₂H₄(Ind)₂MCl₂, C₂H₄(Ind)₂MMe₂, C₂H₄(H₄Ind)₂MCl₂, C₂H₄(H₄Ind)₂MMe₂, Me₂Si(Me₄Cp)₂MCl₂, Me₂Si(Me₄Cp)₂MMe₂, Me₂SiCp₂MCl₂, Me₂SiCp₂MMe₂, Me₂Si(Me₄Cp)₂MMeOMe, Me₂Si(Flu)₂MCl₂, Me₂Si(2-Et-5-iPrCp)₂MCl₂, Me₂Si(H₄Ind)₂MCl₂, Me₂Si(H₄Flu)₂MCl₂, Me₂SiCH₂(Ind)₂MCl₂, Me₂Si(2-Me-H₄Ind)₂MCl₂, Me₂Si(2-MeInd)₂MCl₂, Me₂Si(2-Et-5-iPr-Cp)₂MCl₂, Me₂Si(2-Me-5-EtCp)₂MCl₂, Me₂Si(2-Me-5-Me-Cp)₂MCl₂, Me₂Si(2-Me-4,5-benzoindenyl)₂MCl₂, Me₂Si(4,5-benzoindenyl)₂MCl₂, Me₂Si(2-EtInd)₂MCl₂, Me₂Si(2-iPr-Ind)₂MCl₂, Me₂Si(2-t-butyl-Ind)MCl₂, Me₂Si(3-t-butyl-5-MeCp)₂MCl₂, Me₂Si(3-t-butyl-5-MeCp)₂MMe₂, Me₂Si(2-MeInd)₂MCl₂, C₂H₄(2-Me-4,5-benzoindenyl)₂MCl₂, Me₂C(Flu)CpMCl₂, Ph₂Si(Ind)₂MCl₂, Ph(Me)Si(Ind)₂MCl₂, C₂H₄(H₄Ind)M(NMe₂)OMe, isopropylidene-(3-t-butyl-Cp)(Flu)MCl₂, Me₂C(Me₄Cp)(MeCp)MCl₂, MeSi(Ind)₂MCl₂, Me₂Si(Ind)₂MMe₂, Me₂Si(Me₄Cp)₂MCl(OEt), C₂H₄(Ind)₂M(NMe₂)₂, C₂H₄(Me₄Cp)₂MCl₂, C₂Me₄(Ind)₂MCl₂, Me₂Si(3-Me-Ind)₂MCl₂, C₂H₄(2-Me-Ind)₂MCl₂, C₂H₄(3-Me-Ind)₂MCl₂, C₂H₄(4,7-Me₂-Ind)₂MCl₂, C₂H₄(5,6-Me₂-Ind)₂MCl₂, C₂H₄(2,4,7-Me₃Ind)₂MCl₂, C₂H₄(3,4,7-Me₃Ind)₂MCl₂, C₂H₄(2-Me-H₄Ind)₂MCl₂, C₂H₄(4,7-Me₂-H₄Ind)₂MCl₂, C₂H₄(2,4,7-Me₃-H₄Ind)₂MCl₂, Me₂Si(4,7-Me₂-Ind)₂MCl₂, Me₂Si(5,6-Me₂-Ind)₂MCl₂, Me₂Si(2,4,7-Me₃-H₄Ind)₂MCl₂.
 17. A component according to claim 1 , wherein the transition metal compound is present in a quantity of from 0.1 to 5% by weight expressed as metal.
 18. A catalyst for the polymerization of olefins comprising the product of the reaction of a component according to claim 1 with an alkyl-Al compound selected from trialkyl-Al's in which the alkyl groups have from 1 to 12 carbon atoms and linear or cyclic alumoxane compounds containing the repeating unit —(R₄)AlO—, in which R₄ is an alkyl group with 1-6 carbon atoms or a cycloalkyl or aryl group with 6-10 carbon atoms and containing from 2 to 50 repeating units.
 19. A catalyst according to claim 18 , wherein the alkyl-Al compound is a mixture of trialkyl-Al and an alumoxane.
 20. A catalyst according to claim 18 or 19 , wherein the alumoxane is polymethyl-alumoxane.
 21. A catalyst according to claim 18 or 19 , wherein the trialkyl-Al compound is reacted with 0.5-0.01 mol of water per mole of trialkyl-Al and in which the compound of transition metal M is selected from: C₂H₄(Ind)₂MCl₂, C₂H₄(Ind)₂MMe₂, C₂H₄(H₄Ind)₂MCl₂, C₂H₄(H₄Ind)₂MMe₂, Me₂Si(Me₄Cp)₂MCl₂, Me₂Si(Me₄Cp)₂MMe₂, Me₂SiCp₂MCl₂, Me₂SiCp₂MMe₂, Me₂Si(Me₄Cp)₂MMeOMe, Me₂Si(Flu)₂MCl₂, Me₂Si(2-Et-5-iPrCp)₂MCl₂, Me₂Si(H₄Ind)₂MCl₂, Me₂Si(H₄Flu)₂MCl₂, Me₂SiCH₂(Ind)₂MCl₂, Me₂Si(2-Me-H₄Ind)₂MCl₂, Me₂Si(2-MeInd)₂MCl₂, Me₂Si(2-Et-5-iPr-Cp)₂MCl₂, Me₂Si(2-Me-5-EtCp)₂MCl₂, Me₂Si(2-Me-5-Me-Cp)₂MCl₂, Me₂Si(2-Me-4,5-benzoindenyl)₂MCl₂, Me₂Si(4,5-benzoindenyl)₂MCl₂, Me₂Si(2-EtInd)₂MCl₂, Me₂Si(2-iPr-Ind)₂MCl₂, Me₂Si(2-t-butyl-Ind)MCl₂, Me₂Si(3-t-butyl-5-MeCp)₂MCl₂, Me₂Si(3-t-butyl-5-MeCp)₂MMe₂, Me₂Si(2-MeInd)₂MCl₂, C₂H₄(2-Me-4,5-benzoindenyl)₂MCl₂, Me₂C(Flu)CpMCl₂, Ph₂Si(Ind)₂MCl₂, Ph(Me)Si(Ind)₂MCl₂, C₂H₄(H₄Ind)M(NMe₂)OMe, isopropylidene-(3-t-butylCp)(Flu)MCl₂, Me₂C(Me₄Cp)(MeCp)MCl₂, MeSi(Ind)₂MCl₂, Me₂Si(Ind)₂MMe₂, Me₂Si(Me₄Cp)₂MCl(OEt), C₂H₄(Ind)₂M(NMe₂)₂, C₂H₄(Me₄Cp)₂MCl₂, C₂Me₄(Ind)₂MCl₂, Me₂Si(3-Me-Ind)₂MCl₂, C₂H₄(2-Me-Ind)₂MCl₂, C₂H₄(3-Me-Ind)₂MCl₂, C₂H₄(4,7-Me₂-Ind)₂MCl₂, C₂H₄(5,6-Me₂-Ind)₂MCl₂, C₂H₄(2,4,7-Me₃Ind)₂MCl₂, C₂H₄(3,4,7-Me₃Ind)₂MCl₂, C₂H₄(2-Me-H₄Ind)₂MCl₂, C₂H₄(4,7-Me₂-H₄Ind)₂MCl₂, C₂H₄(2,4,7-Me₃-H₄Ind)₂MCl₂, Me₂Si(4,7-Me₂-Ind)₂MCl₂, Me₂Si(5,6-Me₂-Ind)₂MCl₂, Me₂Si(2,4,7-Me₃-H₄Ind)₂MCl₂.
 22. A process for the polymerization of olefins CH₂═CHR in which R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms or an aryl in which a catalyst according to claim 18 is used.
 23. A process for the polymerization of olefins CH₂═CHR in which R is an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms in which the catalyst used is obtained from a component according to claim 16 .
 24. A process for the polymerization of ethylene and of its mixtures with CH₂═CHR olefins in which R is an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms in which the catalyst used is obtained from a component according to claim 16 .
 25. Polyolefins obtainable from the process of claim 22 .
 26. Manufactured goods obtained from the polymers according to claim 25 . 